Calculators

Air Quality Tools

Practical calculators to help you protect your health during smoke events.

Air Purifier Sizing Calculator

Room size (sq ft)

50 sq ft250 sq ft1,000 sq ft

Number of rooms

11 room8

Min CADR

160

CFM per room

Total for home

160

CFM total

Coverage

250

sq ft total

Based on 8 ft ceilings and 4.8 air changes per hour. Look for HEPA H13 or better. For wildfire smoke, add a carbon pre-filter to capture VOCs.

Cigarette Equivalent

Translate AQI into a relatable metric: equivalent cigarettes smoked, based on Berkeley Air quality research (22 µg/m³ PM2.5 per cigarette per hour).

Outdoor AQI

0150 AQI500

Hours of exposure

1 hr8 hrs24 hrs

Equivalent to smoking

20.1

cigarettes in 8 hours

At AQI 150 · PM2.5 ≈ 55.4 µg/m³

Indoor Protection Estimator

Estimate your effective indoor AQI based on outdoor levels and your protections. A typical home without intervention lets in ~50% of outdoor PM2.5.

Current outdoor AQI

0160 AQI500

Running a HEPA air purifier (−85% indoor PM2.5)Wearing N95 / KN95 mask (−95% filtered)

Estimated indoor AQI

Note:All calculators provide estimates for educational purposes. Actual indoor PM2.5 depends on building construction, HVAC filters, occupant activity, and other factors. Consult EPA's AirNow for official guidance.